IMPORTANT: No additional bug fixes or documentation updates
will be released for this version. For the latest information, see the
current release documentation.
Suspicious WerFault Child Process
editSuspicious WerFault Child Process
editA suspicious WerFault child process was detected, which may indicate an attempt to run via the SilentProcessExit registry key manipulation. Verify process details such as command line, network connections and file writes.
Rule type: eql
Rule indices:
- winlogbeat-*
- logs-endpoint.events.*
- logs-windows.*
- endgame-*
Severity: medium
Risk score: 47
Runs every: 5m
Searches indices from: now-9m (Date Math format, see also Additional look-back time)
Maximum alerts per execution: 100
References:
- https://www.hexacorn.com/blog/2019/09/19/silentprocessexit-quick-look-under-the-hood/
- https://www.hexacorn.com/blog/2019/09/20/werfault-command-line-switches-v0-1/
- https://github.com/sbousseaden/EVTX-ATTACK-SAMPLES/blob/master/Persistence/persistence_SilentProcessExit_ImageHijack_sysmon_13_1.evtx
- https://web.archive.org/web/20230530011556/https://blog.menasec.net/2021/01/
Tags:
- Elastic
- Host
- Windows
- Threat Detection
- Defense Evasion
- Elastic Endgame
Version: 105
Rule authors:
- Elastic
Rule license: Elastic License v2
Investigation guide
editRule query
editprocess where host.os.type == "windows" and event.type == "start" and
process.parent.name : "WerFault.exe" and
/* args -s and -t used to execute a process via SilentProcessExit mechanism */
(process.parent.args : "-s" and process.parent.args : "-t" and process.parent.args : "-c") and
not process.executable : ("?:\\Windows\\SysWOW64\\Initcrypt.exe", "?:\\Program Files (x86)\\Heimdal\\Heimdal.Guard.exe")
Framework: MITRE ATT&CKTM
-
Tactic:
- Name: Defense Evasion
- ID: TA0005
- Reference URL: https://attack.mitre.org/tactics/TA0005/
-
Technique:
- Name: Masquerading
- ID: T1036
- Reference URL: https://attack.mitre.org/techniques/T1036/